The invention lies in the electronics art and pertains, more specifically, to a power supply device and to a circuit configuration having the power supply device.
Japanese patent Abstracts JP 61161967 discloses a power supply device having a temporary energy store, a main energy store and a switching device. The switching device has two switching states. In a first switching state, the temporary energy store is connected to a power supply input and in a second switching state it is connected to the main energy store. The latter is connected to a power supply output. The same applies to European published patent application EP 0 818 875 A2.
European published patent application EP 0 386 261 A1 discloses a similar configuration, with the temporary energy store being switched by means of two switching devices which alternately drive the input and output of the temporary energy store. Furthermore, a configuration for controlling a switching device in a power supply device is described in U.S. Pat. No. 5,278,489.
There exists an increasing need to provide a data processing circuit with secure power supplies. This requirement arises from the fact that there is an increasing need in data processing technology to check whether a data processing circuit may or may not be operated. Attempts are increasingly being made to circumvent such measures, which are based on identification or authentication involved in the process and checking whether operation is or is not allowed. One possibility for gaining unauthorized access to operations or data in a data processing device is the possibility of detecting changes in the power consumption of the data processing device during authorized operation. These changes can then be used to gain access to specific processes and/or data to which access is intrinsically not allowed.
The object of the present invention is to provide a power supply device, and a circuit configuration with a data processing device, which overcome the above-noted deficiencies and disadvantages of the prior art devices and methods of this general kind, and wherein it is not possible to deduce any processes or data in the data processing device by monitoring the power consumption.
With the above and other objects in view there is provided, in accordance with the invention, a power supply device, comprising:
a power supply input and a power supply output;
a switching device having a first switching state, a second switching state, and a third switching state temporally following the second switching state;
a main energy store connected to the power supply output;
a temporary energy store connected to the power supply input in the first switching state and to the main energy store in the second switching state of the switching device; and
an energy discharge device connected to the temporary energy store in the third switching state of the switching device.
In accordance with an added feature of the invention, the switching device is one of a plurality of switching devices and the temporary energy store is one of a plurality of temporary energy stores respectively associated with the switching devices and selectively connectible in parallel with one another to the power supply input and to the main energy store.
In accordance with an additional feature of the invention, the plurality of temporary energy stores are connected to the power supply input at different predetermined times.
In accordance with another feature of the invention, the plurality of temporary energy stores are simultaneously connected to the main energy store.
With the above and other objects in view there is also provided, in accordance with the invention, an integrated circuit configuration comprising a power supply device as outline above and a data processing device connected to the power supply output. The power supply and the data processor are expediently integrated on a common semiconductor chip.
In accordance with a concomitant feature of the invention, the switching device is configured to be operated at a frequency which is less than or equal to a maximum operating frequency of the data processing device.
By decoupling the charged temporary energy store from the power supply input and by changing the charge on the main energy store, the power consumption which can be observed at the power supply input is independent of the instantaneous value of the power consumption which can be observed at the power supply output or which is caused by the data processing device, since the temporary energy store is connected to an energy discharge device once the charge has been transferred to the main energy store.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a power supply device, and a circuit configuration having this power supply device, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.